Train dispatching system for railroads



D 1936. F.'BENEDICT ET AL TRAIN DISPATCHING SYSTEM FOR RAILROADS Filed March 8, 1928 2 Sheets-Sheet l TTORNEY zmmm 2 Sheets-Sheet 2 Filed March 8, 1923 F. BENEDICT El AL RAIN DISPATCHING SYSTEM FORv RAILROADS Aprifi 21,- 1936.

. I VENTO s I Y AT RNEY Patented Apr. 21, 1936 UNITED STATES PATENT OFFICE TRAIN DISPATCHING SYSTEM FOR RAILROADS Application March 8, 1928, Serial No. 260,177

24 Claims.

This invention relates to train dispatching systerns of the way-side signal indicating type, and more particularly to means for OS-ing to the dispatchers ofiice the progress of trains along the trackway.

In railway signalling parlance, the term OS- ing signifies the reporting of a train movement to the dispatchers ofiice. This is usually done manually through operators located at Way stations, ticket ofiices, and the like along the railroad; but in the present application the term OS-ing is used with reference to the automatic indication in the dispatchers office of train movements along the right of Way.

If such OS-ing of train movements is carried on automatically, no difiiculty is experienced so long as this information for a particular way station is transmitted over a separate channel or wire, that is, if a separate Wire is employed for each way station; but if such OS-ing is to be carried out over a single control circuit and from a plurality of way stations, as by distinctive codes, it is necessary that only one way station be permitted to transmit a code at one time. In other words, it is necessary to provide interlock or lockout means whereby only one Way station is permitted to transmit a distinctive code to the dispatchers ofiice at the same time.

In accordance with the present invention, it is proposed to give preference to each Way station as compared with a way station located more distant than the way station in question from the dispatchers office. That is, it is proposed to so interlock the various devices that, if an OS indication is to be transmitted from an intermediate way station, any one of the more distant way stations cannot transmit an OS indication. More specifically, the lockout arrangement embodying the present invention consists of a plurality of over-lapped circuits connected in tumble-down fashion in such a way that the interruptions of any one of these circuits causes a relay to drop and open the next circuit, which next circuit in turn opens a still more remote circuit, similar to the tumble-down circuits used in absolute-permissive-block signalling. By reason of the fact that the lookout arrangement just mentioned may interrupt the transmission of a partially completed code, pro-vision is made for repeating such interrupted code to the tower until a corresponding answer-back code is transmittted from the tower to the way station in question,- the reception of which answer-back.

code manifests the consummation of the OS-ing function and stops the automatic code transmitting means located at such station. The code responsive devices proposed are of a construction to return them to normal when the code is interrupted upon partial completion thereof.

Other objects, purposes, and characteristic fea- 5 tures of the present invention will in part be obvious from the accompanying drawings and in part be more specially described hereinafter.

In describing the invention in detail reference will be made to the accompanying drawings in 10 which:-

Figs. 1A and 1B, if laid end to end, show one embodiment of the present invention, of which Fig. 1A illustrates conventionally the equipment in the dispatchers ofiice and Fig. 13 illustrates 15 conventionally the apparatus at two distant way stations; and

Fig. 2 shows the changed part of a modified form of the invention shown in Figs. 1A and 13.

Referring more particularly to Fig. 1B,' the rails 3 of the main track and the rails 4 of a passing siding PS of a single track railway system is shown divided into blocks and detector track sections by insulating joints 5. These track blocks and detector sections are provided with 25 track batteries 6 and track relays T, to constitute the usual closed track circuit.

Of these track relays, the detector track relays T and T of the detector track circuits associated with the west and east end, respectively, of 30 the passing siding only have been shown. At the east end of the passing siding is track switch T8 and the west end of the siding is a track switch T8 These switches in practice may, if desired, be controlled by suitable power-operated 3:! switch machines, and likewise the signals I, I

2, 2 1, I 8, and 8 associated with these switches may be semi-automatically controlled, all in a mannner as more clearly indicated in the application of S. N. Wight, Ser. No. 120,423 40 filed July 3, 1926.

In the particular form of the invention illustrated each of the detector track relays, such as track relay T for instance, has associated therewith a suitable automatic calling key or code 45 transmittter GT an answer-back selector AS a lookout relay LR. and stick relays S and S1 The manner in which these devices cooperate is more properly pointed out in connection with the operation of the system.

In the dispatchers office, conventionally illustrated by a rectangle D0, is preferably provided a suitable control board or dispatching machine, having associated therewith a miniature track layout corresponding in every detail to the actual railway system to which the invention is applied. For convenience, the miniature passing siding ps of the railway system shown in Fig. IE only has been illustrated in Fig. 1A. In order to indicate the passage of trains over the track switches of the passing siding PS, the miniature track layout ps has been equipped with suitable indicators such as lamps L L associated with the symbolic switches of the miniature passing siding. Each of these indicating lamps, that is, the lamp L for instance, is automatically illuminated and manually extinguished by apparatus including push button P code responsive relay CR and signal relay SR For reasons appearing hereinafter, each group of the dispatchers apparatus also includes a code repeater relay CRR answer-back code transmitter ACT and an answer-back selector A8 The manner in which this apparatus cooperates with the apparatus located at a corresponding way station is more properly described in connection with the operation of the system.

Transmitting an OS indication when not interfered with by a less distant way station.-Let us assume that there is a passing siding PS and that this train in response to the signal 8 in its clear position to which position it was semiautomatically operated by the dispatcher in any suitable manner, as for instance by code-responsive selectors as shown in the application of Dicke, Ser. No. 180,475 filed April 2, 1927.

As this train treads upon the detector track circuit containing track relay T this track relay will close its back contact Ill and close a pick-up circuit for energizing the stick relay S which circuit may be traced as follows:-beginning at the terminal B of the suitable battery, back contact ll of the stick relay SI wire I2, back contact IU of the relay T wires l3 and I4, winding of the stick relay S wire l5, back to common return wire C connected to the other side of said battery. This relay S if once picked up, will be stuck up through the following circuit:beginning at the terminal B of said battery, normally closed code-responsive selector contact I! of the answer-back selector AS wire l8, stick contact I9, wires 20 and I4, winding of the relay S to the common return wire C connected to the other side of said battery. With the relay S energized, the following pick-up circuit for the stick relay SI is closed: starting at the terminal B of said battery, front contact 22 of the relay S wires 23 and 24, winding of the relay S1 to common return wire C connected to the other terminal of said battery. Closure of this pick-up circuit causes the relay SI to assume its energized position and thereby close the following stick circuit, which remains closed so long as the track relay '1 remains deenergized:starting at the terminal B, back contact 25 of track relay T wire 26, stick contact 21 of the relay S1 wires 28 and 24, winding of the relay SI to common return wire C. The purpose of this stick relay S1 is more readily pointed out hereinafter.

With the stick relay S now energized, this because a train has entered the detector track circuit containing track relay T its back contact 30 is opened, thereby opening the following normally closed tumble-down circuit:beginning at the battery BT wires 3| and 32, front contact 33 of the lookout relay LE wire 34, back contact 30 of relay S line wire 35, winding of the lookout relay LE wire 36, to the common return wire CL connected through wire 31 to the negative terminal battery BT It is thus seen that the lockout relay LE of a more distant way station is deenergized and will for reasons pointed out hereinafter, prevent said more distant way station, and any other more distant way station, from transmitting a code to the dispatchers office.

With the stick relay S in its energized condition and with lock relay LE still energized, the following starting circuit for the motor M of the code transmitter CT is closed:beginning at the terminal B front contact 40 of the lookout relay LE wire 4|, front contact 42 of the stick relay S wire 43, motor M to common return wire C. With this motor circuit completed, the code transmitter GT is initiated and if once initiated will remain in operation irrespective of the opening of the starting circuit just traced, because the following stick circuit for the motor M maintains the motor operating until it has reached the end of a cycle and again assumes its normal position:-beginning at the terminal B, motor stick contact 45, wire 46, motor M to common return wire C. With the code transmitter GT once initiated, it will remain in operation until the end of the first cycle even after its starting circuit including front contacts 40 and 42 is broken. In other words, the stick circuit for causing the motor to return to its starting or initial position is closed immediately after the beginning of each operation and is maintained closed until the end of such operation.

With this motor operating and the relays LR and S in their energized condition, a distinctive code depending on the number of teeth and their spaced relation on the code transmitting cam CC is transmitted through the following circuit: beginning at the battery BT wires 3| and 50, front contact 5| of the lockout relay LR wire 52, front contact 53 of the stick relay S wire 54, cam CC cam contact 55, wire 55, coding wire CW, wire 51, winding of the code-responsive selector CR in the dispatchers ofl'ice, wires 58 and 59, common return wire CL, and through wire 31 back to the battery BT The circuit just traced is not the only circuit completed through which the interupted current, comprising a distinctive code, flows; because all of the various code-responsive relays CR CR etc. are connected in multiple and have the interrupted current flowing therein. The distinctive code set up by the coding cam of the code transmitter CT is, however, of such a character as to cause only the closure of the normally open contacts and 6! of the code-responsive relay CR It is believed expedient at this point in the description of the present OS-ing system to consider more specifically the type of code responsive relay or selector that is preferably used. It is proposed to use a code-responsive selector which has inherent characteristics of returning to its normal condition upon interruption of the code, and further one which returns to its initial condition in response to a very simple cancelling code, such as a single impulse followed by an appreciable blank. These features are desired because the transmission of a code from one Way station in the present OS-ing system may be interrupted by a less distant and superior way station even though only partially completed.

One type of selector which is particularly adapted to the present invention is the code responsive selector disclosed in the patent to Field 1,343,256 granted June 15th, 1920, and this selector is preferably used. This selector is one in which a selector in order to respond must receive a definite total number of impulses transmitted in a definite number of groups, each having a definite number of impulses, of which the total number of impulses for all selectors for a particular system is the same. In the particular selector described in said Field patent (see p. 5, l. 80 to 90), the selector responds to 15 impulses, provided these impulses are transmitted in three groups which groups are spaced apart by an interval of time and provided each group contains the necessary number of impulses. This selector is so constructed that it will return to its normal condition unless it has received a number of impulses during the last group of impulses transmitted toprevent the selector returning to its zero position. In other words, if a particular selector is constructed to respond to the code 3-9-3, the transmission of the first three impulses followed by a lapse of time will not allow this particular selector to return to its normal condition, although any other number of impulses would. The next nine impulses will also advance the selector nine more steps and likewise with the next three impulses, so that it has been advanced a total number of fifteen steps to close or open particular contacts. This code responsive selector, as described in the patent to Field, is constructed so that a single impulse followed by a blank of sufiicient duration will cause the selector to return to its initial condition. For this reason, the smallest number of impulses per group as shown in the table on page of said patent is two. The particular code responsive selectors disclosed in the present application, as conventionally shown by the teeth on the coding cams of the various code transmitter, is such as to cause these code responsive relays to close or open their contacts if nine impulses are transmitted in three different groups, each group of which includes the proper number of impulses. The particular code transmitter conventionally shown in this application transmits l0 impulses per cycle of operation of which the first impulse stands by itself and constitutes a cancelling impulse which will return any selector which may not be assuming its normal condition to such normal condition. In other words, the code selector CT transmits a code of 2--4-3, which code is preceded by a single impulse for cancelling purposes. Similarly, the code transmitter GT transmits a code of 2--3-4 which code is preceded by a single impulse for cancelling purposes. In this connection it should be noted that the code transmitter CT and ACT transmit exactlythe same code, this is permissible because the codes transmitted by these two code transmitters are transmitted over different circuits.

The closure of the contact 69 closes the following pick-up circuit for the code-repeater relay CREE-beginning at the terminal B, contact 69 of the selector CR wires 92 and 63, winding of the relay CRR to common return wire C. With the relay CRP once energized even though momentarily, the contact 66 is closed and this relay CRR then remains energized through the following stick circuit-beginning at the terminal B, normally closed contact 64 of the answerback selector AS located at the tower, wire 65, stick contact 66 of the relay CRR wires 61 and 63, winding of the relay ClEtR to common return wire C.

In like manner, momentary closure of the contacts 6| of the code-responsive relay CR completes the following pick-up circuit for the signal relay SR. and picks this relay SR UPC- beginning at the terminal B, wire 10, normally open contact 6| of the relay CR closed only momentarily in response to the reception of the proper code of impulses, wires H and 12, winding of the relay SE. to common return wire C.

With this relay SR once energized, its stick contact 13 is closed and it will remain stuck up through the following stick circuit:-beginning at the terminal B, wire 14, push button contact P wire 15, stick contact 13, wires 16 and i2, winding of the relay SR to common return wire C. With this relay SR. in its energized condition, the energizing circuit for the indicating lamp L readily traced in the drawings and including the contact 11, is closed. If the dispatcher has taken cognizance of the illumination of the indicating lamp L he may depress the push button P and again extinguish the lamp L We have thus far explained how the lamp L is causedto be energized in response to a distinctive code transmitted from the way station associated with the west end of the passing siding PS. As thus far considered, the code transmitter CT is still operating and is repeatedly transmitting this same distinctive code. continued operation of the code transmitter CT is, however, of a short duration because an answer-back code is transmitted from the dispatchers office to the way station in question as soon as the code has been received at the dispatchers office. This answer-back code is of the same character as the code transmitted to energize the indicating lamp L which is possible without interference because the answer-back code is transmitted over a separate circuit. In this connection, it may be pointed out that the answer-back code may be distinctive and may be transmitted over the same circuit if desired, so that only two instead of three line wires would be required.

Let us now observe how the reception of the distinctive code in the dispatchers ofiice causes the answer-back transmitter ACT to be operated, which transmitter will transmit a code to the way station containing track relay 'I and cause cessation of operation of the code transmitter GT With the code repeater relay CRR energized for reasons heretofore given, the closure of its contact 80 will close an energization circuit'for the motor of the code transmitter ACT at the dispatchers ofiice, which circuit is readily traced and includes the battery 8|. With this code transmitter ACT once energized, it will operate to the end of the first cycle even though the contact 89 of relay GER has been retracted, this by reason of the stick circuit for this motor including the stick contact 84. Operation of the answerback code transmitter ACT causes a distinctive code to be transmitted to the various answerback selectors A8 A8 etc. located at the dispatchers office and also at the various way station through circuits of which the following two circuits only will be traced:- (1) beginning at the battery 8|, wire 82, contact 89 of the relay CRR wires 83 and 99 coding contact 9| and coding cam 92 of the code transmitter ACT wires 93, 94, AW and 95, winding of the answerback selector AS located at the corresponding way station, wires 96, CL, and 91 back to the other side of the battery BI; and (2), beginning at battery 8|, wire 82, front contact 80 of the relay CERF, wires 83 and 90, coding contact 9|, cam 92, wires 93 and 98, winding of the answerback selector AS located at the dispatchers of- This:

fice, wires 99, 59 CL and 91 back to the battery 8|.

The reception of the distinctive code in question by the answer-back selector AS located in the dispatchers office, causes momentary opening of the contact 64, thereby deenergizing repeater relay CRR. which in turn efiects deenergization of the motor of the answer-back code selector AGT at the end of its operating cycle. In like manner, the reception of the proper distinctive code in question by the answer-back selector AS located at the corresponding way station effects momentary opening of the normally closed contact ll thereof, thereby causing deenergizaticn of the stick relay S deenergization of which stops operation of the code transmitter GT at the end of the current cycle of operation thereof. That is, dropping of contact 42 of the relay S will not deenergize the motor M because this motor M will receive energy through the stick contact 45 thereof until it has completed its cycle of operation.

Putting it briefly, dropping of the track relay T causes the stick relay S to be stuck up until the code transmitter CT has completed the transmission of a particular code to the dispatchers oflice, has caused initiation of an answer-back code transmitter in the dispatchers oifice, which in turn has transmitted a distinctive code to the answer-back selector AS associated with the code transmitter 0T which by momentary opening of its contact I! drops the stick relay S This causes cessation of operation of this code transmitter GT It should be noted that the stick relay S1 maintains the pick-up circuit for the stick relay S open so long as the track relay T remains deenergized. This provision is made so that if the train under consideration should remain on the detector track circuit containing track relay T for a longer period than is necessary to transmit a distinctive code to the tower and an answer-back code from the tower to the way station, the relay S will nevertheless drop even though contact I8 is closed, and will by such dropping stop operation of the code transmitter GT If after the code transmitter CT has completed its function and has caused momentary opening of the contact I? in response to an answer-back code, the relay S will assume its deenergized condition even though track relay T is still down. As the train in question pulls off of the detector track circuit contain ng track relay T this relay T assumes its energized condition, breaking the stick circuit for the relay S1 and breaking the pickup circuit of the relay S at the contact In so that the relay S1 is re turned to its normal deenergized condition and the relay S is not reenergized. In other words, the stick relay S1 is provided to allow the transmission of a series of distinctive codes to the dispatch rs ofiice once only irrespective of how long the train in question .occupies the detector track, and to also transmit such code even though the train departed before such code was transmitted.

Transmitting an OS indication when there is interference by a less distant way station.-Let us now assume that a less distant way station containing a lockout relay LR and a stick relay S (see Fig, 1A) is trying to transmit a code at a time when the code transmitter CT at the way station containing track relay 1" has just been started and has transmitted only a few impulses.

The moment the less distant way station begins a code transmitting function the relay S is energized, thereby opening its contact H0 and thereby effecting deenergization of the lookout relay LR This will, of course, open the code transmitting circuit including the contact 5| of the lock relay LR thereby not allowing any further transmission of code impulses from the code transmitters CT to the dispatchers office. In this connection, it should be remembered that the code responsive relay preferably employed in connection with the present invention is of the construction shown in the patent to Field 1,343,256 granted June 15th, 1920. It may also be pointed out that this particular code-responsive relay or selector is of a construction that will allow all of the various selectors used in a particular system to return to their normal starting position if the last series of impulses differs from the series of impulses necessary to hold such selector .at its next stopping point. In other words, if a particular code has been partly completed and is then interrupted by reason of the fact that a less distant way station appropriates the use of the coding circuit, all of the various code responsive relays that did not strike a stopping point will return to their normal position ready to respond to the next transmitted code, providing, it is of the proper number of impulses properly grouped as clearly explained in said patent to Field. Those code responsive selectors that did get the right number of impulses to just reach a stopping point will be held at such point. As soon as the code transmitter (not shown) associated with the relay LR starts its code, the single initial or cancelling impulse is first transmitted, and this cancelling impulse will cause those selectors which have not already returned to normal to do so.

Since under the condition now under consideration the relay S is still energized, because it had not completed transmitting its code when the use of the coding line was taken away, the code transmitter GT will again be initiated as soon as the lookout relay LR is again energized. The lockout relay LE is energized as soon as the less distant way station has completed transmitting its OS-ing code, stick relay S being still energized the code transmitter CT is again started and will complete the transmission of a distinctive code to the dispatchers oilice unless it is again interfered with by a less distant way station. In this connection it should be noted that even though the train which occupied the detector track circuit containing relay T has left in the meantime this will not change the condition of relay S (it remaining energized) and the code is nevertheless transmitted.

Modified form.Referring to the apparatus associated with the west end of passing siding PS, it will be noted that the lockout relay LR when deenergized effects deenergization of the lockout relay LE and in this way looks out, so to speak, the more distant way stations. Instead of locking out all of the more distant way stations in this manner, the same lockout function may be accomplished by opening the coding wire CW at a point just beyond the station in question. This may be accomplished by omitting the contact 33 of the lockout relay LE and thus maintaining the lockout relay LE except due to local conditions since it is no longer controlled by the preceding lockout relay and by including the contact HI of this relay LE in the coding Wire CW as shown in Fig. 2 of the drawings. Also if desired.

plurality of overlapping tumble-down circuits so the lockout relay LR may be entirely omitted, in which event contact III is controlled by the relay S Applicants have thus provided a system in which codes may be automatically transmitted from a plurality of way stations to a single dispatchers ofiice over the same control circuit, without the interference of transmission of distinctive codes from a plurality of way stations to the dispatchers office simultaneously, this being accomplished by a lockout circuit arrangement in which every way station is superior to, and has a predominating advantage over, every more distant way station. That is, the lockout arrangement proposed is such as to allow any way station, when it is in condition to transmit an OS signal to the dispatchers ofiice, to appropriate the coding circuit as far as its use, by any more distant way station is concerned.

Having thus shown and described two rather specific embodiments of the present invention, and having disclosed rather specific circuit arrangements for accomplishing certain desired results, it is desired to be understood that this has been done for the purpose of illustrating and explaining the underlying principle of the present invention and not with the idea of disclosing the exact circuit arrangements preferably used in the practicing of the invention, nor have the two exemplifications of the invention been se-.

lected to show the scope of the invention; and it is further desired to be understood that various changes, additions and modifications may be made to adapt the invention to the particular railway system upon which it is to be superimposed, all without departing from the spirit and scope of the invention and the idea of means underlying the same, except as demanded by the scope of the appended claims.

What we claim is:-

1. The method of OS-ing conditions of traffic from a plurality of points along a railway system to the dispatchers office by distinctive codes and over the same indicating circuit, which consists in the provision of automatically-operated code transmitters at said points along the railway system for transmitting distinctive codes to the dispatchers oifice, in ascertaining from the reception of a. distinctive code the event which transpired as well as the location at which it transpired, and in giving each way station superiority as to the use'of the indicating circuit only over all more distant way stations so that no two distinctive codes are transmitted to the dispatchers ofiice at the same time.

2. An OS-ing system for transmitting conditions of trafiic from a plurality of points along a railway system to the dispatchers ofl'ice comprising, means located at each of such plurality of points for transmitting distinctive codes to the dispatchers ofiice over the same indicating circuit, means in the dispatchers office for interpreting these codes, and lockout means for preventing only more distant way stations transmitting codes to the dispatchers oifice when a particular way station is transmitting a code.

3. An OS-ing system for transmitting conditions of traffic from a plurality of points along a railway system to the dispatchers oflice comprising, a dispatchers office, a plurality of way stations, means located at each of said way stations for transmitting a distinctive code of impulses to said dispatchers ofiice over the same indicating circuit, means in the dispatchers office for interpreting said distinctive codes, a

interconnected that if a particular way station is transmitting a code to the dispatchers ofiice all of the more distant tumble-down circuits will be deenergized and will prevent only said more distant way stations from transmitting a code to the dispatchers ofiice.

4. The method of locking out and preventing other way stations from transmitting a distinctive code to the dispatchers ofiice when a particular way station is transmitting a distinctive code in an OS-ing arrangement for train dispatching systems, which consist in giving each way station superiority only overall more distant way stations to the use of a transmitting circuit over which distinctive codes may be transmitted to the dispatchers oiiice, and in allowing only completed codes to be registered in the dispatchers office.

5. An OS-ing system comprising, an automatically-operated calling key at a distinct way station for transmitting a distinctive code to a dispatchers office, a code responsive relay in the dispatchers oflice responsive to the reception of such distinctive code, and means for causing cessation of operation of said automatic calling key responsive to a distinctive code transmitted from the dispatchers office to the corresponding way station after the distinctive code has been transmitted from the way stations in question to the dispatchers'oiiice.

6. A train dispatching system comprising, a dispatchers office, a plurality of code responsive relays in said dispatchers oifice constructed to return to their normal condition after having been changed from normal by a partial code upon reception of a cancelling code, and an automatically-operated calling key located at a distant way station which if initiated will first transmit a cancelling code and then transmit a distinctive code of a character to actuate one of the code responsive relays in the dispatchers ofiice.

7. The method of looking out and preventing other way stations from transmitting a distinctive code to the dispatchers oifice when a particular way station is transmitting a distinctive code in an OS-ing arrangement for train dispatching systems, which consist in automatically impressing distinctive codes on the transmitting circuit upon passage of a train by a way station, and in giving each way station superiority only over all more distant way stations to the use of a transmitting circuit over which distinctive codes may be transmitted to the dispatchers ofiice.

8. In a train OS-ing system, the combination with a local dispatchers office and a plurality of way stations, code responsive receiving means at the dispatchers ofiice, an automatic calling key at each way station, lock out means associated with each of said calling keys each effective to lock out other calling keys when its associated calling key is operating, and means for rendering said lock-out means ineffective responsive to the reception of a particular code of impulses transmitted from the dispatchers ofiice, which particular code of impulses are transmitted in response to reception of a particular code of impulses at the dispatchers oilice from said calling key.

9. A centralized traffic controlling system for railroads, selector means in a central office and at a plurality of way stations to transmit indications of trafiic conditions to said central office one at a time, and storing means for storing a change in trafiic conditions comprising, a track relay, two stick relays, and circuits for causing one of said stick relaysto be picked up-on dropping of said track relay and causing the other of said stick relays to be dropped on picking up of said track relay.

10. A centralized trafllc controlling system for railroads, selector means in a central ofiice and at a plurality of way stations to transmit indications of traffic conditions to said central oilice one at a time, and storing means for storing a change in traific conditions comprising, a track relay, two stick relays, and circuits for causing both of said stick relays to be picked up on dropping of said track relay, causing one of said stick relays to be dropped upon transmission or" such changed condition to said central ofiice, and causing the other of said stick relays to be dropped upon picking up of said track relay.

11. A centralized traffic controlling system for railroads, selector means in a central office and at a plurality of way stations to transmit indications of trafiic conditions to said central office one at a time, a track relay at a distant way station, and storing means for storing a changed condition of said track relay comprising, two stick relays, a pick-up circuit for one of said stick relays including a back contact of said track relay, and a stick circuit for the other of said stick relays including a back contact of said track relay.

12. In combination, a stick relay having a pick-up and a stick circuit, a second relay having a contact in said pick-up circuit closed when said second relay assumes a particular position, means for allowing said stick relay to have its pick-up circuit closed for a time only in response to a change in said second relay to such particular position including a second stick relay having a stick circuit including a contact closed only if said second relay assumes said particular position, code responsive means for opening thestick circuit of said first mentioned stick relay, and a code transmitting means set into operation when said first mentioned stick relay is picked up.

13. In combination, a stick relay having a pick-up and a stick circuit, a second relay having a contact in said pick-up circuit closed when said second relay assumes a particular position, means for allowing said stick relay to have its pick-up circuit close-d for a time only in response to a change in said second relay to such particular position including a second stick relay having a stick circuit including a. contact closed only if said second relay assumes said particular position, and code type indicating means controlled by said first mentioned stick relay.

14. In combination; a track relay controlled by the presence and absence of trafiic on a section of a railroad track; a first and a second stick relay; a pick-up circuit for said first stick relay including a contact of said track relay closed when said track relay is in a particular position, and a back contact of said second stick relay; a pick-up circuit for said second stick relay including a front contact of said first stick relay; a stick circuit for said second stick relay; means for energizing said stick circuit only when said track relay is in said particular position; a code type communication system set into operation when said first stick relay is picked up, and a stick circuit for said first stick relay, controlled by said code type communication system.

15. In combination, a trafiic controlled relay,

first and second stick relays, a pick up circuit for said first stick relay including a contact of said traflic controlled relay closed with said trafiic controlled relay in a particular position and a back contact of said second stick relay, a pick up circuit for said second stick relay including a front contact of said first stick relay, a stick circuit for said second stick relay including a contact of said traffic controlled relay closed with said traffic controlled relay in a particular position, a normally at rest multiple impulse type communication system set into a cycle of operation by said first stick relay, and means opening said stick circuit for said first stick relay upon the completion of a cycle of op eration of said communication system, whereby said first stick relay has its pick up circuit closedfirst stick relay is picked up, a stick circuit for said second stick relay closed only when said track relay is in said particular position, a stick circuit for said first stick relay, a communication system of the code type set into operation when said first stick relay is picked up and means for opening said stick circuit for said first stick relay remotely controlled over said communication system.

1'7. In a centralized.v traffic controlling system for railroads, a line circuit connecting two stations, transmitting means at one of said stations capable of impressing a code on said line circuit when initiated into operation, a starting relay for initiating said transmitting means into operation when such starting relay is picked up, code receiving means at both of said stations responsive to the codes applied to said line circuit, and a stick circuit for said starting relay closed when said starting relay is once picked up until said code receiving means at said one station has responded to the code impressed by said transmitting means. 4

18. In a centralized traffic controlling system for railroads, a line circuit connecting two stations, transmitting means at one of said stations capable of impressing a code on said line circuit when initiated into operation, a starting relay for initiating said transmitting means into operation when such starting relay is picked up, code receiving means at both of said stations responsive to the codes applied to said line circuit, a stick circuit for said starting relay closed when said starting relay is once picked up until said code receiving means at said one station has responded to the code impressed by said transmitting means, and means responsive to traffic conditions for at times picking up said starting relay.

19. In a centralized trafiic controlling system for railroads, a line circuit connecting a control ofiice and a plurality of field stations; transmitting means at each of the field stations for impressing difierent codes on said line circuit; receiving means at the control office distinctively responsive to each of the codes impressed on said line circuit; and lockout means at each field station for preventing all other field stations from transmitting when that field station is transmitting, said lockout means at each field station being effective when that particular station starts to transmit for stopping the transmitter of any station more distant from the control office that may be operating and for restoring said receiving means in the control ofiice to normal ready for the reception of a code from such station.

20. In a centralized traffic controlling system for railroads; a line circuit connecting a control office and a plurality of field stations; transmitting means at each of the field stations for transmitting different codes over said line circuit to the control office; receiving means at the control office distinctively responsive to each of the codes transmitted over said line circuit; a lookout relay at each field station for preventing the field stations more distant from the control ofiice from transmitting when that field station is transmitting, said relay being effective when picked up; traffic controlled means for at times picking up said relay; and a stick circuit for said relay closed. until said transmitting means at that station has transmitted its code to the control oifice and a code has been transfitted from the control office to that field station signifying the proper transmission from such field station.

21. In a centralized traflic controlling system for railroads; a line circuit connecting a control office and a plurality of field stations; transmitting means at each of the field stations for transmitting different codes over said line circuit to the control office; receiving means at the control ofiice distinctively responsive to each of the codes transmitted over said line circuit; a lookout relay at each field station for preventing the field stations more distant from the control office from transmitting when that field station is transmitting, said relay being eifective when picked up; traffic controlled means for at times picking up said relay; and means governable from the control office for rendering said lockout relay ineffective.

22. In a centralized traffic controlling system for railroads; a line circuit connecting a control office and a plurality of field stations; transmitting means at each of the field stations for transmitting different codes over said line circuit to the control office; receiving means at the control office distinctively responsive to each of the codes transmitted over said line circuit; a starting relay at each field station for initiating said transmittng means at that station into operation when such starting relay is rendered effective; traffic controlled means for at times rendering said starting relay effective; and means governable from the control office for at times rendering said starting relay ineffective.

23. In a centralized traffic controlling system for railroads; first and second line circuits connecting a control office and a field station; transmitting means at the field station for transmitting codes over said first line circuit to the control office; receiving means at the control ofiice responsive to each of the codes transmitted over said first line circuit; a starting relay at the field station for initiating said transmitting means into operation when such starting relay is rendered effective; traffic controlled means for at times rendering said starting relay effective; and means controlled from the control office by a code transmitted over said second line circuit for rendering said starting relay ineffective.

24. In a centralized traffic controlling system for railroads; a line circuit connecting a control office and a field station; transmitting means at the field station for transmitting codes over said line circuit to the control office; receiving means at the control office responsive to each of the codes transmitted over said line circuit; a starting relay at the station for initiating saidtransmitting means into operation when such starting relay is energized; trafiic controlled means at the field station, means governed by said traffic control means for at times energizing said starting relay, and means operated from the control oifice for deenergizing' said starting relay.

FRANK BENEDICT. PAUL E. CARTER.

DISCLAIMER 2,037,875.-Franlc Benedict, Rutherford, N. J., and Paul E. Carter, Bronxville, N. Y. TRAIN DISPATCHING SYSTEM FOR RAILROADS. Patent dated April 21, 1936.

Disclaimer filed January 17, 1938, by the assignee, General Railway Signal Company.

Hereby enters this disclaimer to Patent.

claims 2, 6, 19, 21, 22, and 24 of said Letters [Ofiic'ial Gazette February 8, 1.988.] 

